Color photographic processing

ABSTRACT

A METHOD OF COLOR PROCESSING FOR A PHOTOGRAPHIC LIGHTSENSITIVE COLOR ELEMENT COMPRISING, AT LEST, DEVELOPMENT, STOP-FIXING, AND BLEACH-FIXING, THE IMPROVEMENT WHICH COMPRISING PROCESSING THE LIGHT-SENSITIVE ELEMENT IN A BATH CONTAINING A WATER-SOLUBLE IRON COMPLEX SALT AND A COMPOUND REPRESENTED BY THE GENERAL FORMULA.   H2N(ANH)NANH2   WHEREIN A REPRESENTS AN ALKYLENE GROUP HAVING FROM 2 TO 3 CARBON ATOMS AND N IS A POSITIVE INTEGER, THE BATH BEING A BLEACH-FIXING BATH OR A SEPARATE BATH IN WHICH THE ELEMENT IS PROCESSED, AFTER COLOR DEVELOPMENT, BUT NO LATER THAN BLEACH-FIXING.

United States Patent Office Patented May 11, 1971 Int. Cl. ooscs/sz, /38

US. C]. 96-60 12 Claims ABSTRACT OF THE DISCLOSURE A method of color processing for a photographic lightsensitive color element comprising, at least, development, stop-fixing, and bleach-fixing, the improvement which comprising processing the light-sensitive element in a bath containing a water-soluble iron complex salt and a compound represented by the general formula:

wherein A represents an alkylene group having from 2 to 4 carbon atoms and n is a positive integer, the bath being a bleach-fixing bath or a separate bath in which the element is processed, after color development, but no later than bleach-fixing.

BACKGROUND OF THE INVENTION (1) Field of the invention The present invention relates to color photographic processing and more particularly to a bleaching process for color development, and to such a process using a solution containing a specific compound.

(2) Description of the prior art The procedures of color development processes generally include a color development, stop-fixing, bleaching (de-silvering), fix-cleaning, hardening, stabilizing and some additional processings. Each of the baths used in these processings has its own composition fitted to its purpose.

Typical bleaching solutions for color development processing contain potassium ferricyanide or a water-soluble iron complex salt, such as, Fe +-ethylenediaminetetraacetic acid complex.

ing accelerators have been investigated to increase the bleaching power of the bath (e.g., German Patent 1,127,715), but an additive with sufiicient accelerating power has not yet been discovered.

As an example of a bleaching accelerator, it has been known to incorporate thiourea or thiourea derivatives in bleach-fixing baths but the incorporation in the bleachfixing bath is accompanied by faults, such as, the con- In the case of using potassium ferricyanide, the solution has enough ability to bleach developed silver, therefore the degradation in image quality caused by insufficient bleaching will not occur. However, when potassium ferricyanide is present together with a thiosulfate which is used as a fixing agent, the thiosulfate will be decomposed by potassium ferricyanide because of its high oxidizing power; that is, the bleaching solution containing ferricyanide has the disadvantage that the bleaching bath must be separated from the fixing bath, which prolongs the process considerably. Furthermore, there is also another disadvantage in that potassium ferricyanide is unstable in the solution and tends to be converted into potassium ferricyanide.

On the other hand, a water-soluble iron coplex salt, such as Fe +-ethylenediaminetetraacetic acid complex, can exist stably even in the presence of a thiosulfate. Therefore, simultaneous bleaching and fixing in one bath (blixing) is possible. However, the bleaching power of the bleach-fixing bath containing an iron complex salt and a thiosulfate is not sufficient. Hence, various bleachtamination of the bleach-fixing solution with color degeloping solution causing considerable increase in color Therefore, an object of the present invention is to provide a color development process having a sufiicient bleaching power and providing no color fog. Another object of this invention is to provide a color development process using a bleach-fixing solution containing a watersoluble iron complex salt having sufi'icient bleaching power and giving no color fog. Still another object of the present invention is to provide a color development process able to give a good colored image by applying bleach-fixing rfliirectly after color development without applying stopxing.

SUMMARY OF THE INVENTION The inventors have studied ways to attain the aforesaid objects and as a result, it has been found that these objects are achieved by the incorporation in a bleach-fixing bath of the color photography compound represented by the general formula H N(ANH),,ANH 1 wherein A represents an alkylene group having 24 carbon atoms, and n is a positive integer. This additive markedly increases the bleaching power of the bath and also improves the color fog preventing effect. Moreover, in regard to the bleaching accelerator eifect, the aforesaid compound may be effectively added to the stop-bleaching bath or a bath between the stop-bleaching bath and the bleach-fixing bath. In another aspect, that is, in regard to the prevention of color fog, the aforesaid compound may very eifectively be added to a bath between the' color developer and the stop-fixing bath, to the stop-fixing bath, or to the bath between a stop-fixing bath and a bleachfixing bath.

In the case of conventional color photographic processing, if a stopper or a stop-fixing bath is omitted and the photographic elements are bleach-fixed (blixed) directly after color development, there occurs color fog which is considered to be caused by the color developer which remains in the emulsion layers. Hence, in practice, the stop-fixing process cannot be neglected in conventional processing systems. On the other hand, incorporation of compound (1) mentioned above in a processing bath between the color development and the bleach-fixing or in the bleach-fixing bath, according to the present invention, sufiiciently prevents the formation of color fog. Hence, the stop-fixing bath is not always necessary.

Now, it is known that some of the compounds (1) are reported to be a kind of reduction sensitizer for silver halide emulsions (e.g., US. Patent 2,518,698), but when the compound is used in the amount employed in the known art, or is added to emulsions during the preparation thereof, neither the bleaching promoting eflect, nor the color fog preventing effect of this invention can be obtained.

DETAILED DESCRIPTION OF THE INVENTION Typical examples of compounds used in the present invention expressed by the aforesaid general Formula l are as follows: However, the invention is, of course, not limited only to them.

Polyethylene imine formula:

and is available commercially under the trade name Sumirez Resin P (average polymerization degree 'y=about 100 made by Somitomo Chemical Industries Co. Ltd., in Japan.

In addition, the amount of the aforesaid composition added to the processing solution is generally 0.3 g./liter to 50 g./liter preferably 2 g./liter to 10 g./liter. Since the compound of this invention is alkaline, the pH of the bleach-fixing bath must be adjusted to 6.4-7.1.

The aforesaid compounds may be used alone or as a combination of two or more of them.

Now, the invention will be described by the following examples wherein the bleach-promoting effect and the color fog preventing effect of the aforesaid compounds 2 minutes in the aqueous solution thus prepared and then bleach-fixed. The time required for completion of the bleaching was measured in each case including a control experiment in which the aqueous solution was not used. The results are shown below.

Additive: Time (minutes) Compound 1 5 Compound 2 5 Compound 3 5 Compound 4 5 Compound 5 5 Compound 6 6 As is clear from the experimental results, it was confirmed that in the case of employing an aqueous solution of the compound of this invention, the bleach-accelerating effect in the subsequent bleach-fixing bath was excellent.

Further, the stains of the samples processed by the aqueous solution of the compound of the present invention were compared with the stains of a sample which was not processed by'the aqueous solution. The results are shown in the following table.

Compound Stain 1 2 3 4 5 Control Yellow stain 0.10 0.10 0.10 0.10 0.10 0.25 Magentastain 0.10 0.10 0.10 0.10 0.10 0.18 Cyanstain 0.08 0.08 0.08 0.08 0.08 0.21

are illustrated. However, it should be understood that the invention is not limited to these examples.

Example 1.Into one liter of a bleach-fixing bath of the following composition was added 10 g. of each of aforesaid Compounds 15.

G. Iron salt of ethylenediaminetetraacetic acid 34 Boric acid 45 Sodium thiosulfate 140 Additive 10 Water to make 1000 ml. pH 6.8:02.

The control bleach-fixing 'bath for comparison had the following composition:

G. Iron salt of ethylenediaminetetraacetic acid 34 Sodium carbonate (mono-hydrate) 11 Boric acid 45 Sodium thiosulfate 140 Water to make 1000 ml. pH 6.8:02.

An exposed color print paper was color developed, stopfixed, then processed in the bleach-fixing bath of the above formula and the time needed for bleaching was determined. The results are shown below.

Additive: Time (minutes) Compound 1 2 Compound 2 2 Compound 3 2 Compound 4 2 Compound 5 2 None 6 As is clear from the experimental results, the formation of stains on the color print was markedly reduced by the aqueous solution of the compound of this invention. The processing temperature in these experiments was 24 C.

When color films were processed, almost the same results were obtained.

Example 3.After exposure and color development, a color print paper was directly immersed in the bleachfixing bath prepared in Example 1 for 3 minutes without processing in a stopping bath or stop-fixing bath. As a control experiment, the same color print paper was immersed for 3 minutes in a bleach-fixing bath containing no compound of this invention under the same conditions. The formation of stains was compared in both cases, the results of which are shown in the following table, in which each stain was shown by three color densities.

As is clear from the results, Compounds 1-5 of this invention showed very excellent stain preventing effect.

In these experiments, the developed silver on the color print paper was completely bleached in 3 minutes of blixing by the bath containing the compound of this invention, whereas the developed silver was not completely bleached in the case of the bath containing no compounds of this invention. The processing temperature in these experiments was 24 C. When color films were processed as above, almost the same results were obtained.

What is claimed is:

1. In a method of color processing a photographic light-sensitive color element comprising image-wise exposing the element, developing the exposed element by a developer capable of forming a silver and a color image adn bleach-fixing the developed element to remove the silver image, the improvement which comprises processing the color element after development in a bleach-fixing bath containing a water-soluble iron complex salt and an amine compound represented by the general formula:

wherein A represents an alkylene group having from 2 to 4 carbon atoms and n is 0 or a positive integer, the amount of said amine compound being from about 0.3 g. to about 50 g. per one liter of the bleach-fixing bath.

2. The method of color processing as claimed in claim 1 wherein said amine compound is selected from the group consisting of H NCH --CH -NH imine.

3. The method of color processing as claimed in claim 1 wherein said water-soluble iron complex salt is the iron salt Fe +-ethylenediamine-tetraacetic acid.

4. The method of claim 1 wherein from 2 g. to g. of said amine compound are present per liter.

5. The method of claim 1 wherein the pH of the bleach-fixing bath is from 6.4 to 7.1.

6. In a method of color processing a photographic lightsensitive color element comprising image-wise exposing the element, developing the exposed element by a developer capable of forming a silver and a color image and bleach-fixing the developed element to remove the silver image, the improvement which comprises processing the color element after development but prior to bleach-fixing in a bath containing an amine compound represented by the general formula:

H N (ANH) ANH wherein A represents an alkylene group having from 2 to 4 carbon atoms and n is 0 or a positive integer, and subsequently bleach-fixing said color element in a bleach-fixing bath containing a water-soluble iron complex salt, the amount of said amine compound in said bath being from about 0.3 g. to about 50 g. per one liter of said bath.

7. The method of color processing as claimed in claim 6 wherein said compound is selected from the group consisting of H N-CH CH -NH 8. The method of color processing as claimed in claim 6 wherein said water-soluble iron complex salt is the iron salt Fe +-ethylenediamine-tetraacetic acid.

9. The method of claim 6 wherein from 2 g. to 10 g. of said amine compound are present per liter.

10. The method of claim 6 wherein the pH of the bleach-fixing bath is from 6.4 to 7.1.

11. The method of claim 6 wherein the bath in which said amine compound is present is a stop-bleaching bath.

12. The method of claim 6 wherein the processing of said color element after color development includes a stop-bleaching bath prior to processing in said bleach-fixing bath, and said amine compound is present in a bath between said stop-bleaching bath and said bleach-fixing bath.

References Cited UNITED STATES PATENTS 2,310,981 2/1943 Meschter 96-22 2,322,084 6/ 1943 Young et al. 96-53 2,706,687 4/1955 Rees et al. 96-61X 2,857,275 10/1958 Land et al. 96-61X 3,141,771 7/1964 Bard et al. 96-22 3,168,400 2/1965 Blackmer et al. 96-22 3,169,992 2/1965 Henn 96-61X 3,256,092 6/1966 Means et al. 96-60 2,827,375 3/ 1958 Andreyev 96-62X 3,259,497 7/ 1966 Wartburg 96-60X 3,271,153 9/1966 Miller et a1 96-61 3,352,676 11/1967 Morcher et al. 96-22X 3,372,030 3/ 1968 Jacobson 96-60UX FOREIGN PATENTS 739,202 10/ 1955 Great Britain 96-60 717,018 8/1965 Canada 96-60 WILLIAM D. MARTIN, Primary Examiner H. J. GWINNELL, Assistant Examiner US. Cl. X.R. 

